Summary: | The well-known field of engineering psychology, also known as human factors engineering, utilizes psychologists to solve Engineering's problems that concern the behavior of humans in their operation and control of engineering systems such as military aircraft. To limit psychology's relation to engineering this way is, however, counterproductive. Psychology requires a broader conceptualization of engineering psychology, a subfield of psychology, within which the psychologist's major concern is with the behavior of psychoengineering systems that affect the reliability, validity and safety of psychological research and practice. In contrast with human-factor systems, the psychoengineering systems include healthy and unhealthy, human and animal subjects. The affiliated problems are not those of the engineering industry. This study in engineering psychology concerned the safety of two electrical stimulation systems that are used on animals, chiefly dogs, in punishment and escape/avoidance conditioning procedures of psychology. The study referenced two safety questions. First, is the electricity, when applied externally to the ventral neck of the animal, capable of stimulating carotide sinus and vagus nerves to the point of dangerously disrupting systemic blood pressure and sinus rhythm? Second, is the electricity capable of damaging the epidermis when it is applied repeatedly to the same two points of contact? Of forty-two anesthetized dogs, half were tested with a punishment system; the remainder were tested with an escape/avoidance system. Each was stimulated for five seconds, five times, at each of five intensities. Inter-stimulus interval was about thirty seconds. Systemic blood pressures and electrocardiograms (ECG) were recorded. Control and experimental biopsies were taken for histological examinations of electrified and unelectrified specimens. Each animal's neck was examined grossly each day for ten days following the stimulation runs. None of the gross examination reports was positive. An exact binomial test supported the hypothesis that tissue samples from control and experimental biopsies did not differ histologically. Repeated measure ANOVAs were used to detect significant differences in systolic pressures, diastolic pressures, and R to R intervals of the ECG throughout stimulation runs. While there were some statistically significant results, there was no clinical significance, especially with regard to safety hazards.
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